| 1 | #! /usr/bin/env python
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| 2 |
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| 3 | # Simulate "electrons" migrating across the screen.
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| 4 | # An optional bitmap file in can be in the background.
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| 5 | #
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| 6 | # Usage: electrons [n [bitmapfile]]
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| 7 | #
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| 8 | # n is the number of electrons to animate; default is 30.
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| 9 | #
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| 10 | # The bitmap file can be any X11 bitmap file (look in
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| 11 | # /usr/include/X11/bitmaps for samples); it is displayed as the
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| 12 | # background of the animation. Default is no bitmap.
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| 13 |
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| 14 | from Tkinter import *
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| 15 | import random
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| 16 |
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| 17 |
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| 18 | # The graphical interface
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| 19 | class Electrons:
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| 20 |
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| 21 | # Create our objects
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| 22 | def __init__(self, n, bitmap = None):
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| 23 | self.n = n
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| 24 | self.tk = tk = Tk()
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| 25 | self.canvas = c = Canvas(tk)
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| 26 | c.pack()
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| 27 | width, height = tk.getint(c['width']), tk.getint(c['height'])
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| 28 |
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| 29 | # Add background bitmap
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| 30 | if bitmap:
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| 31 | self.bitmap = c.create_bitmap(width/2, height/2,
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| 32 | bitmap=bitmap,
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| 33 | foreground='blue')
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| 34 |
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| 35 | self.pieces = []
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| 36 | x1, y1, x2, y2 = 10,70,14,74
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| 37 | for i in range(n):
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| 38 | p = c.create_oval(x1, y1, x2, y2, fill='red')
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| 39 | self.pieces.append(p)
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| 40 | y1, y2 = y1 +2, y2 + 2
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| 41 | self.tk.update()
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| 42 |
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| 43 | def random_move(self, n):
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| 44 | c = self.canvas
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| 45 | for p in self.pieces:
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| 46 | x = random.choice(range(-2,4))
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| 47 | y = random.choice(range(-3,4))
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| 48 | c.move(p, x, y)
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| 49 | self.tk.update()
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| 50 |
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| 51 | # Run -- allow 500 movemens
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| 52 | def run(self):
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| 53 | try:
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| 54 | for i in range(500):
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| 55 | self.random_move(self.n)
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| 56 | except TclError:
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| 57 | try:
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| 58 | self.tk.destroy()
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| 59 | except TclError:
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| 60 | pass
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| 61 |
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| 62 |
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| 63 | # Main program
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| 64 | def main():
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| 65 | import sys, string
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| 66 |
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| 67 | # First argument is number of electrons, default 30
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| 68 | if sys.argv[1:]:
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| 69 | n = string.atoi(sys.argv[1])
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| 70 | else:
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| 71 | n = 30
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| 72 |
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| 73 | # Second argument is bitmap file, default none
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| 74 | if sys.argv[2:]:
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| 75 | bitmap = sys.argv[2]
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| 76 | # Reverse meaning of leading '@' compared to Tk
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| 77 | if bitmap[0] == '@': bitmap = bitmap[1:]
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| 78 | else: bitmap = '@' + bitmap
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| 79 | else:
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| 80 | bitmap = None
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| 81 |
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| 82 | # Create the graphical objects...
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| 83 | h = Electrons(n, bitmap)
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| 84 |
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| 85 | # ...and run!
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| 86 | h.run()
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| 87 |
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| 88 |
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| 89 | # Call main when run as script
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| 90 | if __name__ == '__main__':
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| 91 | main()
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